Observation of extremely strong shock waves in solids launched by petawatt laser heating

PHYSICS OF PLASMAS 24 (2017) ARTN 083115

KL Lancaster, APL Robinson, J Pasley, P Hakel, T Ma, K Highbarger, FN Beg, SN Chen, RL Daskalova, RR Freeman, JS Green, H Habara, P Jaanimagi, MH Key, J King, R Kodama, K Krushelnick, H Nakamura, M Nakatsutsumi, AJ MacKinnon, AG MacPhee, RB Stephens, L Van Woerkom, PA Norreys

Attosecond-scale absorption at extreme intensities

Physics of Plasmas 24 (2017)

AF Savin, AJ Ross, M Serzans, RMGM Trines, L Ceurvorst, N Ratan, B Spiers, R Bingham, APL Robinson, PA Norreys

© 2017 Author(s). A novel non-ponderomotive absorption mechanism, originally presented by Baeva et al. [Phys. Plasmas 18, 056702 (2011)] in one dimension, is extended into higher dimensions for the first time. This absorption mechanism, the Zero Vector Potential (ZVP), is expected to dominate the interactions of ultra-intense laser pulses with critically over-dense plasmas such as those that are expected with the Extreme Light Infrastructure laser systems. It is shown that the mathematical form of the ZVP mechanism and its key scaling relations found by Baeva et al. in 1D are identically reproduced in higher dimensions. The two dimensional particle-in-cell simulations are then used to validate both the qualitative and quantitative predictions of the theory.

Brilliant X-rays using a Two-Stage Plasma Insertion Device.

Scientific reports 7 (2017) 3985-

JA Holloway, PA Norreys, AGR Thomas, R Bartolini, R Bingham, J Nydell, RMGM Trines, R Walker, M Wing

Particle accelerators have made an enormous impact in all fields of natural sciences, from elementary particle physics, to the imaging of proteins and the development of new pharmaceuticals. Modern light sources have advanced many fields by providing extraordinarily bright, short X-ray pulses. Here we present a novel numerical study, demonstrating that existing third generation light sources can significantly enhance the brightness and photon energy of their X-ray pulses by undulating their beams within plasma wakefields. This study shows that a three order of magnitude increase in X-ray brightness and over an order of magnitude increase in X-ray photon energy is achieved by passing a 3 GeV electron beam through a two-stage plasma insertion device. The production mechanism micro-bunches the electron beam and ensures the pulses are radially polarised on creation. We also demonstrate that the micro-bunched electron beam is itself an effective wakefield driver that can potentially accelerate a witness electron beam up to 6 GeV.

Dense plasma heating by crossing relativistic electron beams.

Physical review. E 95 (2017) 013211-

N Ratan, NJ Sircombe, L Ceurvorst, J Sadler, MF Kasim, J Holloway, MC Levy, R Trines, R Bingham, PA Norreys

Here we investigate, using relativistic fluid theory and Vlasov-Maxwell simulations, the local heating of a dense plasma by two crossing electron beams. Heating occurs as an instability of the electron beams drives Langmuir waves, which couple nonlinearly into damped ion-acoustic waves. Simulations show a factor 2.8 increase in electron kinetic energy with a coupling efficiency of 18%. Our results support applications to the production of warm dense matter and as a driver for inertial fusion plasmas.

Nonlinear parametric resonance of relativistic electrons with a linearly polarized laser pulse in a plasma channel

Physics of Plasmas 24 (2017)

TW Huang, CT Zhou, APL Robinson, B Qiao, AV Arefiev, PA Norreys, XT He, SC Ruan

© 2017 Author(s). The direct laser-acceleration mechanism, nonlinear parametric resonance, of relativistic electrons in a linearly polarized laser-produced plasma channel is examined by a self-consistent model including the relativistic laser dispersion in plasmas. Nonlinear parametric resonance can be excited, and the oscillation amplitude of electrons grows exponentially when the betatron frequency of electron motion varies roughly twice the natural frequency of the oscillator. It is shown analytically that the region of parametric resonance is defined by the self-similar parameter n e /n c a 0 . The width of this region decreases with n e /n c a 0 , but the energy gain and oscillation amplitude increases. In this regime, the electron transverse momentum grows faster than that in the linear classical resonance regime.

Excitation and Control of Plasma Wakefields by Multiple Laser Pulses


J Cowley, C Thornton, C Arran, RJ Shalloo, L Corner, G Cheung, CD Gregory, SPD Mangles, NH Matlis, DR Symes, R Walczak, SM Hooker

Machine learning applied to proton radiography of high-energy-density plasmas.

Physical review. E 95 (2017) 043305-

NFY Chen, MF Kasim, L Ceurvorst, N Ratan, J Sadler, MC Levy, R Trines, R Bingham, P Norreys

Proton radiography is a technique extensively used to resolve magnetic field structures in high-energy-density plasmas, revealing a whole variety of interesting phenomena such as magnetic reconnection and collisionless shocks found in astrophysical systems. Existing methods of analyzing proton radiographs give mostly qualitative results or specific quantitative parameters, such as magnetic field strength, and recent work showed that the line-integrated transverse magnetic field can be reconstructed in specific regimes where many simplifying assumptions were needed. Using artificial neural networks, we demonstrate for the first time 3D reconstruction of magnetic fields in the nonlinear regime, an improvement over existing methods, which reconstruct only in 2D and in the linear regime. A proof of concept is presented here, with mean reconstruction errors of less than 5% even after introducing noise. We demonstrate that over the long term, this approach is more computationally efficient compared to other techniques. We also highlight the need for proton tomography because (i) certain field structures cannot be reconstructed from a single radiograph and (ii) errors can be further reduced when reconstruction is performed on radiographs generated by proton beams fired in different directions.

The Coherent Combination of Fibre Lasers - Towards Realistic Applications


P Tudor, L Corner, R Walczak, AIP

Quantitative shadowgraphy and proton radiography for large intensity modulations.

Physical review. E 95 (2017) 023306-

MF Kasim, L Ceurvorst, N Ratan, J Sadler, N Chen, A Sävert, R Trines, R Bingham, PN Burrows, MC Kaluza, P Norreys

Shadowgraphy is a technique widely used to diagnose objects or systems in various fields in physics and engineering. In shadowgraphy, an optical beam is deflected by the object and then the intensity modulation is captured on a screen placed some distance away. However, retrieving quantitative information from the shadowgrams themselves is a challenging task because of the nonlinear nature of the process. Here, we present a method to retrieve quantitative information from shadowgrams, based on computational geometry. This process can also be applied to proton radiography for electric and magnetic field diagnosis in high-energy-density plasmas and has been benchmarked using a toroidal magnetic field as the object, among others. It is shown that the method can accurately retrieve quantitative parameters with error bars less than 10%, even when caustics are present. The method is also shown to be robust enough to process real experimental results with simple pre- and postprocessing techniques. This adds a powerful tool for research in various fields in engineering and physics for both techniques.

Absolute multilateration between spheres


J Muelaner, W Wadsworth, M Azini, G Mullineux, B Hughes, A Reichold

Optimization of plasma amplifiers.

Physical review. E 95 (2017) 053211-

JD Sadler, RMGM Trines, M Tabak, D Haberberger, DH Froula, AS Davies, S Bucht, LO Silva, EP Alves, F Fiúza, L Ceurvorst, N Ratan, MF Kasim, R Bingham, PA Norreys

Plasma amplifiers offer a route to side-step limitations on chirped pulse amplification and generate laser pulses at the power frontier. They compress long pulses by transferring energy to a shorter pulse via the Raman or Brillouin instabilities. We present an extensive kinetic numerical study of the three-dimensional parameter space for the Raman case. Further particle-in-cell simulations find the optimal seed pulse parameters for experimentally relevant constraints. The high-efficiency self-similar behavior is observed only for seeds shorter than the linear Raman growth time. A test case similar to an upcoming experiment at the Laboratory for Laser Energetics is found to maintain good transverse coherence and high-energy efficiency. Effective compression of a 10kJ, nanosecond-long driver pulse is also demonstrated in a 15-cm-long amplifier.

Robustness of raman plasma amplifiers and their potential for attosecond pulse generation


JD Sadler, M Sliwa, T Miller, MF Kasim, N Ratan, L Ceurvorst, A Savin, R Aboushelbaya, PA Norreys, D Haberberger, AS Davies, S Bucht, DH Froula, J Vieira, RA Fonseca, LO Silva, R Bingham, K Glize, RMGM Trines

High flux, beamed neutron sources employing deuteron-rich ion beams from D<inf>2</inf>O-ice layered targets

Plasma Physics and Controlled Fusion 59 (2017)

A Alejo, AG Krygier, H Ahmed, JT Morrison, RJ Clarke, J Fuchs, A Green, JS Green, D Jung, A Kleinschmidt, Z Najmudin, H Nakamura, P Norreys, M Notley, M Oliver, M Roth, L Vassura, M Zepf, M Borghesi, RR Freeman, S Kar

© 2017 IOP Publishing Ltd. A forwardly-peaked bright neutron source was produced using a laser-driven, deuteron-rich ion beam in a pitcher-catcher scenario. A proton-free ion source was produced via target normal sheath acceleration from Au foils having a thin layer of D 2 O ice at the rear side, irradiated by sub-petawatt laser pulses (∼200 J, ∼750 fs) at peak intensity . The neutrons were preferentially produced in a beam of ∼70 FWHM cone along the ion beam forward direction, with maximum energy up to ∼40 MeV and a peak flux along the axis for neutron energy above 2.5 MeV. The experimental data is in good agreement with the simulations carried out for the d(d,n) 3 He reaction using the deuteron beam produced by the ice-layered target.

Magnetic field generation during intense laser channelling in underdense plasma

Physics of Plasmas 23 (2016)

AG Smyth, G Sarri, M Vranic, Y Amano, D Doria, E Guillaume, H Habara, R Heathcote, G Hicks, Z Najmudin, H Nakamura, PA Norreys, S Kar, LO Silva, KA Tanaka, J Vieira, M Borghesi

© 2016 Author(s). Channel formation during the propagation of a high-energy (120 J) and long duration (30 ps) laser pulse through an underdense deuterium plasma has been spatially and temporally resolved via means of a proton imaging technique, with intrinsic resolutions of a few μm and a few ps, respectively. Conclusive proof is provided that strong azimuthally symmetric magnetic fields with a strength of around 0.5 MG are created inside the channel, consistent with the generation of a collimated beam of relativistic electrons. The inferred electron beam characteristics may have implications for the cone-free fast-ignition scheme of inertial confinement fusion.

Current Status and Future Prospects of the SNO plus Experiment


S Andringa, E Arushanova, S Asahi, M Askins, DJ Auty, AR Back, Z Barnard, N Barros, EW Beier, A Bialek, SD Biller, E Blucher, R Bonventre, D Braid, E Caden, E Callaghan, J Caravaca, J Carvalho, L Cavalli, D Chauhan, M Chen, O Chkvorets, K Clark, B Cleveland, IT Coulter, D Cressy, X Dai, C Darrach, B Davis-Purcell, R Deen, MM Depatie, F Descamps, F Di Lodovico, N Duhaime, F Duncan, J Dunger, E Falk, N Fatemighomi, R Ford, P Gorel, C Grant, S Grullon, E Guillian, AL Hallin, D Hallman, S Hans, J Hartnell, P Harvey, M Hedayatipour, WJ Heintzelman, RL Helmer, B Hreljac, J Hu, Iida, CM Jackson, NA Jelley, C Jillings, C Jones, PG Jones, K Kamdin, T Kaptanoglu, J Kaspar, P Keener, P Khaghani, L Kippenbrock, JR Klein, R Knapik, JN Kofron, LL Kormos, S Korte, C Kraus, CB Krauss, K Labe, I Lam, C Lan, BJ Land, S Langrock, A LaTorre, I Lawson, GM Lefeuvre, EJ Leming, J Lidgard, X Liu, Y Liu, V Lozza, S Maguire, A Maio, K Majumdar, S Manecki, J Maneira, E Marzec, A Mastbaum, N McCauley, AB McDonald, JE McMillan, P Mekarski, C Miller, Y Mohan, E Mony, MJ Mottram, V Novikov, HM O'Keeffe, E O'Sullivan, GDO Gann, J Parnell, SJM Peeters, T Pershing, Z Petriw, G Prior, JC Prouty, S Quirk, A Reichold, A Robertson, J Rose, R Rosero, PM Rost, J Rumleskie, MA Schumaker, MH Schwendener, D Scislowski, J Secrest, M Seddighin, L Segui, S Seibert, T Shantz, TM Shokair, L Sibley, JR Sinclair, K Singh, P Skensved, A Soerensen, T Sonley, R Stainforth, M Strait, MI Stringer, R Svoboda, J Tatar, L Tian, N Tolich, J Tseng, HWC Tseung, R Van Berg, E Vzquez-Jauregui, C Virtue, B von Krosigk, JMG Walker, M Walker, O Wasalski, J Waterfield, RF White, JR Wilson, TJ Winchester, A Wright, M Yeh, T Zhao, K Zuber

Numerical study of neutron beam divergence in a beam-fusion scenario employing laser driven ions


A Alejo, A Green, H Ahmed, APL Robinson, M Cerchez, R Clarke, D Doria, S Dorkings, J Fernandez, P McKenna, SR Mirfayzi, K Naughton, D Neely, P Norreys, C Peth, H Powell, JA Ruiz, J Swain, O Willi, M Borghesi, S Kar

AWAKE: A Proton-Driven Plasma Wakefield Acceleration Experiment at CERN


C Bracco, LD Amorim, R Assmann, F Batsch, R Bingham, G Burt, B Buttenschoen, A Butterworth, A Caldwell, S Chattopadhyay, S Cipiccia, LC Deacon, S Doebert, U Dorda, E Feldbaumer, RA Fonseca, V Fedossev, B Goddard, J Grebenyuk, O Grulke, E Gschwendtner, J Hansen, C Hessler, W Hofle, J Holloway, D Jaroszynski, M Jenkins, L Jensen, S Jolly, R Jones, MF Kasim, N Lopes, K Lotov, SR Mandry, M Martyanov, M Meddahi, O Mete, V Minakov, J Moody, P Muggli, Z Najmudin, PA Norreys, E Oez, A Pardons, A Petrenko, A Pukhov, K Rieger, O Reimann, AA Seryi, E Shaposhnikova, P Sherwood, LO Silva, A Sosedkin, R Tarkeshian, RMGM Trines, FM Velotti, J Vieira, H Vincke, C Welsch, M Wing, G Xia

Beamed neutron emission driven by laser accelerated light ions


S Kar, A Green, H Ahmed, A Alejo, APL Robinson, M Cerchez, R Clarke, D Doria, S Dorkings, J Fernandez, SR Mirfayzi, P McKenna, K Naughton, D Neely, P Norreys, C Peth, H Powell, JA Ruiz, J Swain, O Willi, M Borghesi

Characteristics of betatron radiation from direct-laser-accelerated electrons

Physical Review E - Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics (2016)

PA Norreys

Generation of laser pulse trains for tests of multi-pulse laser wakefield acceleration


RJ Shalloo, L Corner, C Arran, J Cowley, G Cheung, C Thornton, R Walczak, SM Hooker